He's 91. I'm sure there are other cartoonists that have worked into their nineties, and certainly if you expand this to include comics-makers of all types than the just-turned-91 Stan Lee still has some creative projects out there with at least on them, but I'm not sure anyone matches Mizuki's age with his heft and his unique celebrity.

I think comics does better than a lot of art forms in terms of finding legitimate, respectable places for a lot of older creators to make work, but even that isn't something that extends to all expressions of the art form.